In order to realize a decrease in the weight of a turbine vane of a steam turbine and a steam turbine, there is known a technique of a hollow structure in which a space is formed inside the turbine vane. Further, in order to realize improvement in the performance of the turbine vane of the steam turbine and the steam turbine, there is proposed a technique in which the turbine vane is provided with slits for causing the inner space of the turbine vane to communicate with the outside and water (steam and water droplet) adhering to the surface of the turbine vane is brought into the inner space of the turbine vane so as to be removed therefrom (for example, see Japanese Patent Publication No. 11-336503).
In the turbine vane of the hollow structure, there is a case in which self-excited vibration (flutter) is generated in response to the outer shape (geometrical shape) or the mass of the turbine vane and the circumferential environment of the turbine vane during the operation of the turbine (for example, the flow velocity or the mass of the steam passing through the turbine vane). The self-excited vibration is easily generated when the mass of the turbine vane is small and the vane width (the entire length of the vane) is long. Particularly, in order to obtain the high efficiency of the turbine in recent years, there is a tendency that the mass of the turbine vane is decreased and the vane width is lengthened. For this reason, there is a tendency that the self-excited vibration is more easily generated.
Therefore, in the turbine vane of the hollow structure, a technique capable of suppressing the self-excited vibration is proposed (for example, see Japanese Patent Publication No. 2008-133825). In this technique, a slidable contact member (plate spring member) capable of slidably contacting (elastically contacting) the vane inner surface (the inner surface of the vane member) from the hollow space (the inner space) is provided. In this technique, when the turbine vane is elastically deformed, the slidable contact member slidably contacts the vane inner surface from the hollow space. Accordingly, friction is generated between the vane inner surface and the slidable contact member, and the elastic deformation of the turbine vane is reduced by the friction, so that the self-excited vibration generated in the turbine vane is suppressed.
Here, the self-excited vibration generated in the turbine vane may be reliably suppressed as the area in which the slidable contact member slidably contacts the vane inner surface is widened. Incidentally, there is a case in which the slidable contact member partially contacts the vane inner surface due to the manufacturing tolerances (manufacturing variation) of the turbine vane and the slidable contact member, so that a slidable contact area according to a design (a plan and a calculation) may not be obtained.
In this way, in the turbine vane of the steam turbine and the steam turbine, it is important to devise a structure capable of reliably suppressing the self-excited vibration generated in the turbine vane in a manner such that the manufacturing tolerances of the turbine vane and the slidable contact member are absorbed so that the slidable contact member slidably contacts the vane inner surface according to the design and the slidable contact area is obtained according to the design.